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Function in the stunted forelimbs of Mononykus olecranus (Theropoda), a dinosaurian anteater

Published online by Cambridge University Press:  08 April 2016

Phil Senter
Phil Senter*
Affiliation:
Department of Math and Science, Lamar State College at Orange, 410 Front Street, Orange, Texas 76630. E-mail: [email protected]
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Abstract

Mononykus olecranus, a theropod dinosaur from the Upper Cretaceous of Mongolia, exhibits reduced forelimbs with a single functional digit. These bizarre forelimbs have aroused great curiosity as to the behavior of the animal, but until now no functional study on the forelimbs of Mononykus has been undertaken. Here I show that the orientation and range of motion in the forelimb elements of Mononykus are such that the humeri sprawl laterally, the antebrachia are held subvertically, the palms face ventrally, and intramanual movement is restricted to subparasagittal motion. This is a radical departure from the typical theropod condition, in which the palms face medially and intramanual movement is transverse. The results of this study confirm that the forelimbs of Mononykus could not have been used to grasp prey or dig burrows, but were well suited for scratch-digging or hook-and-pull movements such as are used by extant anteaters and pangolins to open tough insect nests. Mononykus likely occupied a niche equivalent to that of an anteater or pangolin, an unusual niche for a dinosaur.

Type
Articles
Information
Paleobiology , Volume 31 , Issue 3 , Summer 2005 , pp. 373 - 381
Copyright
Copyright © The Paleontological Society 

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